In order to make aircraft passengers comfortable, and in order to transport them between an airport terminal and an aircraft in such a way that they are protected from weather and other environmental influences, passenger loading bridges are used which can be telescopically extended and the height of which is adjustable. For instance, an apron drive bridge in present day use comprises a plurality of adjustable modules, including: a rotunda, a telescopic tunnel, a bubble section, a cab, and elevating columns with wheel carriage. Manual, semi-automated and automated bridge alignment systems are known for adjusting the position of the passenger loading bridge relative to an aircraft, for instance to compensate for different sized aircraft and to compensate for imprecise parking of an aircraft at an airport terminal, etc. Of course, other types of bridges are known in the art, such as for example nose loaders, radial bridges and pedestal bridges.
Unfortunately, aircraft aisle design is such that passenger flow rate along aircraft aisles is a limiting factor, which slows down the entire deplaning operation. That is, the aircraft doorways and most passenger loading devices are capable of handling substantially higher passenger flow rates than are the aircraft aisles. Of course, similar delays are also encountered during the boarding, or enplaning, operation. This limitation is of serious concern in a marketplace where airlines consistently struggle to shorten the turn-around time of their aircraft in order to boost operating efficiency, lower operating costs and thereby offer lower fares to their customers.
Accordingly, there has been much interest over the past several decades in developing ways of servicing plural doorways of a same aircraft, in order to reduce the length of time that is required to complete the boarding and deplaning operations for said aircraft. Although it is known to service more than one doorway in front of the wing of some types of large aircraft, for example using two separate apron drive bridges to service two different doorways, the actual time savings are nominal because some passengers must still traverse a long stretch of in-plane aisle in order to reach the nearer of the two different doorways.
Some types of aircraft include a rear door through which passengers can enter and leave the aircraft by means of steps that are lowered from the aircraft onto the apron or tarmac, or by means of mobile steps that are connected to the door by ground personnel. One drawback with this approach is that it is necessary for passengers to walk onto the apron and then walk up steps into the passenger bridge. As will be obvious to one of skill in the art, it is not desirable for passengers to occupy the apron surrounding an aircraft, because of the safety risks involved. Additionally, accessibility may be a concern for some passengers, such as for instance a passenger using a wheelchair.
An improved system for servicing a doorway behind or over the wing of aircraft equipped with such a doorway is required. In particular, many smaller types of aircraft, such as for instance narrow body aircraft, have only a single aisle along which passengers are able to traverse the distance between the front of the aircraft and the last row of seats in the back of the aircraft. By servicing the rear doorway, the length of in-plane aisle which the passenger must traverse may be reduced substantially, for example by a factor of up to two, with a corresponding reduction of the boarding and/or deplaning time. This is particularly desirable in the case of “stretch” models of aircraft, in which the length of in-plane aisle that must be traversed by passengers can be quite significant. This reduction in boarding and/or deplaning time not only avoids adverse passenger reaction, but also substantially increases safety during situations requiring fast deplaning as in the case of a fire on the ramp or in the aircraft at the terminal.
There have been two basic techniques of positioning aircraft alongside passenger terminals to permit interconnection of the aircraft and the terminal using passenger bridges; these two techniques are parallel parking and nose-in parking. Parallel parking offers the advantages that the aircraft arrives and departs from its parked position under its own power, and thus requires no tow tractor in its turnaround cycle. Further, the orientation of the aircraft with respect to the terminal facade in parallel parking facilitates access to aircraft doorways either forward of or aft of the wing with known ramp supported loading bridges. Moore et al. in U.S. Pat. No. 3,184,772, issued May 25, 1965, disclose a telescoping loading and unloading structure for servicing doorways forward of and aft of the wing of an aircraft parked in parallel relationship to a terminal building.
However, parallel parking presents one very significant disadvantage. Parallel parking necessitates certain aircraft turning and maneuvering room, and therefore this technique requires greater terminal facade length than does the nose-in technique. Another disadvantage of parallel parking is that departure of an aircraft from a parked parallel position requires substantial engine thrust to start and turn the aircraft. As the aircraft departs, the exhaust of the aircraft engines is directed toward the terminal building and toward the ground equipment and personnel located adjacent the terminal with a resultant shaking of the terminal building and disruption of ground operation activities.
In view of these disadvantages, most modern terminals utilize nose-in aircraft parking. However, with nose in parking, it is generally necessary to cantilever or otherwise move a passenger loading bridge structure directly over the aircraft wing in order to service the rear doorway. One exception is U.S. Pat. No. 3,808,626 issued to Magill on May 7, 1974, in which a self contained mobile passenger loading bridge for airplane loading and unloading operations is disclosed. The bridge comprises a three section telescopic passageway, which is pivotally connected to a terminal building at an inboard end via a stationary rotunda and to a moveable rotunda at an outboard end. A second, two section telescopic passageway is pivotally connected to the moveable rotunda at an inboard end thereof and has a cabin at an outboard end thereof for engaging a rear doorway of an aircraft. The bridge is essentially an elongated conventional apron drive bridge having an additional pivot point, i.e. the moveable rotunda, for steering the outboard end behind the wing of a nose-in parked aircraft in order to mate the cabin to a rear doorway of the aircraft.
U.S. Pat. No. 3,524,207 issued to Giarretto Aug. 18, 1970 discloses an over-the-wing access structure for servicing multiple doors in commercial jet aircraft. The height of the structure is vertically adjustable in a level manner so as to accommodate vertical movement of the aircraft during loading and unloading. This system is both awkward and expensive. Furthermore, should power to the structure be interrupted when the outboard supports are deployed, it becomes impossible to move the aircraft away from the terminal building due to the supports blocking the path of the wings.
U.S. Pat. No. 3,538,529 issued to Breier on Nov. 10, 1970 discloses an overhead supported aircraft loading bridge, including a slightly arched telescoping tunnel section, which may be cantilevered over the wing of an aircraft for servicing a rear doorway thereof. The telescoping tunnel section is pivotally connected to a static structure, thereby providing additional freedom of vertical motion for clearing the wing and mating to the rear door of the aircraft. This system also is both awkward and expensive. It is a further disadvantage of this system that the overhead support arm must support the weight of the entire loading bridge. Accordingly, the loading bridge of US '529 is particularly unsuitable for use with “stretch” aircraft models, which models have rear doorways that are serviceable only using loading bridges having three telescoping tunnel sections. As will be obvious to one skilled in the art, an additional tunnel section would add unacceptably to the weight of the loading bridge disclosed by Breier.
U.S. Pat. No. 3,722,017 issued to Gacs et al. on Mar. 27, 1973 discloses an over-the-wing aircraft loading bridge having a main passageway member pivotally supported at the terminal building end on a track mounted rack propelled carriage. The main passageway member is elevatable and depressable so that its outer end portion, slightly arched, may extend over the wing of an aircraft. At its outer end the main passageway mounts a lateral passageway including an operator's cab, which is for being mated to a rear doorway of the aircraft. The lateral passageway appears to serve as a bridge between the rear doorway and the main passageway element, which passageway lacks sufficient freedom of vertical movement to engage the rear doorway directly. It is a disadvantage of this system that the lateral passageway, including the mechanism for adjusting same, adds considerable weight to the unsupported (i.e. outboard) end of the main passageway member. The additional complexity of aligning such a bridge would increase the time required to move the bridge into alignment with the rear doorway, thereby negating some of the desired time savings. It is a further disadvantage of the system disclosed by Gacs et al. that additional bridge operators and gate control staff are required to service the multiple doors of the aircraft. For example, each doorway of the aircraft is serviced using a separate bridge having a separate entrance into the terminal area.
Anderberg in WO 9942365 discloses an over-the-wing bridge having a telescopic tunnel section pivotally connected to a rotunda at an inboard end thereof and terminating in a cabin at an outboard end thereof. The outboard end is supported using a vertically adjustable wheel carriage, which requires the outboard end of the tunnel to be driven outward and around the wing of the aircraft. Of course, should power to the telescopic tunnel be interrupted when the rear doorway of the aircraft is engaged, it becomes impossible to move the aircraft away from the terminal building due to the wheel carriage blocking the path of the wing. Furthermore, the tunnel section is straight and therefore the floor of the cabin is at a lower level relative to the floor of the outermost tunnel section. Although this arrangement allows the telescopic tunnel section to clear the wing of the aircraft, the steps that are necessary for connecting the two floor sections would constitute an unacceptable barrier to universal accessibility.
Kubatzki in WO 0009395 discloses an over the wing bridge including at least one horizontally pivotal extension arm, which extension arm is mounted on a support. An access tunnel, including a device on the end thereof for docking to the aircraft, is coupled to the extension arm. Due to the length of the cantilevered section of the passenger bridge, the extension arm and support are necessarily structures of considerable size and complexity. Furthermore, the support structure severely limits the ability of the bridge to pivot horizontally.
Worpenberg in WO 0055040 discloses an over-the-wing bridge including a telescopic tunnel section that can be swiveled over the wing of an aircraft and which is supported by an extension arm that is fixedly or moveably mounted on a frame. The telescopic tunnel section is straight, and as such the inboard end of the tunnel section must be at a higher level relative to the outboard end of the tunnel section in order to engage the rear doorway of an aircraft whilst maintaining acceptable clearance above the aircraft wing. This may result in the upward slope of the telescopic tunnel section toward the terminal being unacceptably steep.
FMT Aircraft Gate Support Systems of Sweden has recently implemented a dual-door, over-the-wing loading bridge. The bridge includes a passageway extending from a rotunda and which can be cantilevered over the wing of an aircraft to mate a cabin at the outboard end of the passageway to a rear doorway of the aircraft. The passageway is supported at a variable height by an adjustable wheel carriage in front of the wing and is permanently arched at a predetermined angle. Accordingly, vertical swinging motion occurs only at a point where the bridge is mounted to a fixed structure, such as one of a rotunda and a terminal building. It is a disadvantage that for certain combinations of fixed structure access height and aircraft rear doorway position, servicing the rear doorway is awkward or impossible due to the limited vertical motion of the cabin end.
It would be advantageous to provide an over-the-wing aircraft loading bridge that overcomes the above-mentioned disadvantages associated with the prior art.